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Site Report: Tesoro - Northstore #9

Site Name: Tesoro - Northstore #9
Address: 2401 Spenard Road &1104 West Fireweed Lane, Anchorage, AK 99503
File Number: 2100.26.083
Hazard ID: 23720
Status: Cleanup Complete
Staff: No Longer Assigned, 9074655229 dec.icunit@alaska.gov
Latitude: 61.198800
Longitude: -149.905000
Horizontal Datum:NAD83

We make every effort to ensure the data presented here is accurate based on the best available information currently on file with DEC. It is therefore subject to change as new information becomes available. We recommend contacting the assigned project staff prior to making decisions based on this information.

Problems/Comments

During the inspection for needed upgrades of the one 5,000-gallon diesel, and two 10,000-gallon gasoline underground storage tanks, diesel, gasoline, and benzene soil and groundwater contamination was encountered as a result of over filling and/or during filling. Approximately 908.03 tons of contaminated soil was excavated and thermally treated at Alaska Soil Recycling in Anchorage. A soil vapor extraction system was installed, and long-term groundwater monitoring established. The vapor extraction system was ineffective, so and air sparge groundwater treatment system was installed and remains operable. Updated 2-22-07 by Paul Horwath.

Action Information

Action Date Action Description DEC Staff
11/27/1996 Leaking Underground Storage Tank Release Confirmed - Petroleum LUST Site created in CSP for source area ID 77811 ADD; Gasoline contamination. Dept received letter from RP's consultant advising that sampling done on 10/29/96 showed that the subsurface soils were contaminated around the USTs at this site. Former Staff
11/27/1996 Site Added to Database Former Staff
11/5/1997 Update or Other Action Dept advises RP and consultant by letter that Krieber is now the PM. Former Staff
11/20/1997 Update or Other Action ADEC sends Notification of Intent to Cost Recover Letter to Current Owner: TESORO NORTHSTORE Former Staff
2/17/1998 Leaking Underground Storage Tank Corrective Action Underway Dept received proposed workplan from consultant for action at this site in 1998. Former Staff
3/10/1998 Update or Other Action Dept reviewed workplan and issues letter of approval. Former Staff
9/11/1998 Update or Other Action Tanks upgraded with CP rather than closing them. Additional contamination found. Former Staff
12/16/1998 Underground Storage Tank Site Characterization or Assessment SA Report received from consultant. Former Staff
12/16/1998 Leaking Underground Storage Tank Corrective Action Underway Dept received a CA Workplan for the site. Former Staff
1/6/1999 Update or Other Action Dept reviews and responds to SA Report. Former Staff
2/9/1999 Update or Other Action Dept approves CA Workplan. Former Staff
4/12/1999 Leaking Underground Storage Tank Cleanup Initiated - Petroleum Approval granted by Dept for transport and treatment of contaminated soils from drilling for MWs for the RI that was initiated at this site. Former Staff
5/5/1999 Release Investigation RI Report received from the consultant. Former Staff
6/4/1999 Update or Other Action Dept reviews and responds to RI Report. Former Staff
7/21/1999 Leaking Underground Storage Tank Corrective Action Underway Proposed WP for Phase 2 RI and CAP received by the Dept. Former Staff
7/22/1999 Update or Other Action Dept sent ltr, expressing some concerns on the proposed WP. Former Staff
8/11/1999 Long Term Monitoring Established Quarterly Monitoring Report received. Former Staff
8/20/1999 Update or Other Action Well search report received by the Dept. Former Staff
9/15/1999 Update or Other Action Dept reviews and responds to Well Search Report. Former Staff
9/23/1999 Update or Other Action Dept reviews and responds to Quarterly Monitoring Report. Former Staff
11/23/1999 Release Investigation Installation of three more wells (4,5,6) to detect offsite contamination. GW and soil clean. Reviewed by JBC 4/19/00. Former Staff
1/25/2000 Update or Other Action Department reviews and approves of Pilot test - acknowledges that equipment specs are consultant's decision, but general objectives were met. Former Staff
2/15/2001 Release Investigation JBC: Install three additional wells to replace MW1-3 that were removed as part of tank removals. Installed three replacement monitoring/SVE wells and initiated treatement at the site. Groundwater to NW, E, and SW offsite is clean. Contamination appears to be at the edge of the property to north and west, but does not likely extend far beneath the roadway. Former Staff
4/4/2001 Long Term Monitoring Established February 2001 Monitoring Event report received from Gilfilian Engineering. Monica English
7/19/2001 Long Term Monitoring Established May 2001 Monitoring Event report received from Gilfilian Engineering. Monica English
11/1/2001 Long Term Monitoring Established August 2001 Monitoring Event report received from Gilfilian Engineering. Monica English
2/1/2002 Long Term Monitoring Established November 2001 Monitoring Event report received from Gilfilian Engineering. Monica English
5/1/2002 Long Term Monitoring Established Received February 2002 Monitoring Event report from Gilfilian Engineering. Monica English
9/1/2002 Long Term Monitoring Established Received May 2002 Monitoring Event report from MWH. Monica English
2/2/2004 Release Investigation Approval issued for 2004 Work plan. Monica English
10/4/2004 Update or Other Action File number issued 2100.26.083 Aggie Blandford
11/1/2004 Document, Report, or Work plan Review - other April 2004 Monitoring Event Report. GW contaminant trends consistent with previous sampling. Monitor well MW2 exceeds GCL for benzene, GRO and DRO. The AS remediation system continues to operate. Monica English
11/15/2004 Update or Other Action Staff attends annual environmental planning meeting with Tesoro and MWH to discuss workplans for 2005. Monica English
11/18/2004 Update or Other Action File number 2100.26.083 assigned and entered into the Fileroom DB and LUST DB. Alyce Hughey
1/25/2005 Update or Other Action ADEC issues approval for the 2005 calendar year Corrective Action plan. Monica English
11/17/2005 Leaking Underground Storage Tank Corrective Action Underway Monica English sent an approval letter for the Corrective Action Work Plan for 2006. Alyce Hughey
10/9/2006 Update or Other Action Project manager changed from Monica English to Paul Horwath, per Paul Horwath. Alyce Hughey
11/29/2006 Update or Other Action Using Figure 1 from the December 2002 Monitoring Event, Air Sparge Well Installation and SVE Pilot Study Report, from Montgomery Watson Harza, dated February 2003, in conjunction with TopoZone Pro and the Recorders Office, and Anchorage Live, entered the coordinates for this site. Metadata includes No Topo Basemap, Black and White Aerial Photo, TopoZone Pro Street Maps, on a Medium Size Map, View Scale 1:9,840, Coordinate Datum NAD83. High degree of confidence in accuracy of location. Alyce Hughey
2/22/2007 Document, Report, or Work plan Review - other Reviewed MWH's Tesoro 2 Go Mart #9, October 2006 Monitoring Event Report Final, dated December 2006. Air sparge treatment continues to be operated at this site, and GW remains contaminated with DRO, GRO, benzene, and ethylbenzene. GW contaminate concentrations increased from the prior sampling event, but all in all are considered stable, and have diminished since air sparge treatment began in the fall of 2002. Paul Horwath
4/9/2007 Leaking Underground Storage Tank Corrective Action Underway Approved MWH's Work Plan for Confirmation Soil Borings, Tesoro 2 Go Mart #9, dated February 16, 2007. Eight soil borings and one new GW monitoring wells will be installed at this site in 2007. Paul Horwath
4/10/2007 Exposure Tracking Model Ranking Initial ETM ranking completed. Paul Horwath
9/27/2007 Update or Other Action ADEC authorized the transport of 55 gallons of petroleum contaminated soil from this site to ASR in Anchorage. Post-treatment analyses required of ASR include BTEX, GRO, and DRO. Paul Horwath
10/31/2007 Update or Other Action Provide a written response to ASR's request for a closure letter for contaminated soils received from this site. Paul Horwath
12/20/2007 Document, Report, or Work plan Review - other Reviewed the April 2007 Monitoring Event Report prepared by MWH, dated July 2007. GW contamination levels have decreased since treatment began in 2002, however levels have remained steady for the past several years, and still exceed ADEC GW cleanup levels. Air sparge groundwater treatment occuring at this time. An additional MW is to be installed down-gradient of the residual GW contamination. Paul Horwath
4/17/2008 Document, Report, or Work plan Review - other Reviewed the October 2007 Monitoring Event Report Final prepared by MWH, dated February 2008. GW contamination levels have decreased since treatment began in 2002, however levels have remained steady for the past several years in MW-2, and still exceed ADEC GW cleanup levels. Air sparge groundwater treatment continues at this time. An additional MW is to be installed down-gradient of the known residual GW contamination in order to establish the downgradient extent of contamination. Paul Horwath
9/17/2008 Document, Report, or Work plan Review - other Reviewed the August 2007 Confirmation Soil Borings Report, from MWH, dated June 2008 for Paul Horwath and provided him a review of the report for his review. Petroleum soil contamination was encountered that exceeds the soil cleanup levels for Benzene, Toluene, Ethylbenzene, Xylenes, GRO, and DRO. A work plan needs to be preparted to address the remaining contamination issues for the site. Alyce Hughey
9/18/2008 Document, Report, or Work plan Review - other Reviewed the April 2008 Monitoring Event Report, from MWH, dated July 2008 for Paul Horwath and provided him a summary of the report for his review. Groundwater concentrations in MW-2 remain steady at a level just above the groundwater cleanup levels, where the concentrations in MW-3 have decreased to a level below the groundwater cleanup levels for two consecutive quarters. Alyce Hughey
9/25/2008 Document, Report, or Work plan Review - other Review MWH's April 2008 Monitoring Event Report, dated July 2008. Identify issues with lab data validation by MWH. Contact MWH to obtain corrections to the ADEC Lab Data Review Checklist, and groundwater flow direction and gradient did not correspond to the elevations listed in the body of the report and within Figure 2. Paul Horwath
10/22/2008 Document, Report, or Work plan Review - other Reviewed and discussed with Paul Horwath MWH's April 2008 Monitoring Event Report (Revised), dated October 2008. Issues with the lab data valadation were addressed, and erroneous elevation values were used to create the original plot. The corrected values were plotted and the amended GW direction and gradient were inserted into the report. Alyce Hughey
12/17/2008 Update or Other Action Reviewed the October 2008 Monitoring Event Report, dated November 2008, from MWH for Paul Horwath and provided him with a summary of the report for his review and oversight. Site conditions continue to improve with groundwater concentrations in MW-2 continuing to decrease with only DRO remaining above the groundwater cleanup level; were the concentrations in MW-3 have remained undetected for all the analytes for three consecutive monitoring events. Alyce Hughey
2/26/2009 Document, Report, or Work plan Review - other Reviewed the November 2008 Monitoring Well Installation and Monitoring Event report, dated December 2008, from MWH for Paul Horwath and provided him a summary for his review and oversight. During the installation of an additional monitoring well to the north of the site, MW-7, Benzene was detected above the soil cleanup levels at a depth of 18 feet below ground surface, which is where groundwater was encountered. Toluene, Ethylbenzene, Xylenes and GRO was detected in the soil at a depth of 18 feet below ground surface but remained below the soil cleanup levels. The groundwater sample taken from the new monitoring well, MW-7 detected Benzene and Xylenes that were below the groundwater cleanup levels. The results of the monitoring well installation, indicates that off-site migration of Benzene contamination has occurred at this site. Alyce Hughey
4/14/2009 Document, Report, or Work plan Review - other Reviewed the January 2009 Monitoring Event Report, dated March 2009, from MWH for Paul Horwath and prepared a summary for his review and oversight. The contaminant concentrations in MW-2, which is located north and down gradient of the former underground storage tanks have been oscillating near the groundwater cleanup levels since 2003, and MW-3 has remained below the groundwater cleanup levels since 2005. Only minor traces of contamination are being detected in the new monitoring well installed off site during the month of November of 2008. A work plan outlining additional remediation actions will be submitted to ADEC during 2009 in order to better address the remaining contamination at the site. Alyce Hughey
8/24/2009 Document, Report, or Work plan Review - other Reviewed and approved the Supplemental Work Plan for Chemical Oxidation Treatment, dated August 14, 2009 for the Tesoro Northstore #9, from MWH. Paul Horwath
11/24/2009 Document, Report, or Work plan Review - other Reviewed the July 2009 Monitoring Event Report, dated September 2009, from MWH for Paul Horwath and prepared a summary for his review and oversight. The July 2009 groundwater monitoring event indicated an increase in Benzene, GRO and DRO groundwater concentrations in MW-2. MW-3 remains undetected for all the analytes tested for. In order to address the remaining contamination MWH has started chemical oxidation treatments using Potassium Permanganate by injecting it into the subsurface within the zone of contamination via several direct-push wells. Data presented at the annual ADEC/Tesoro meeting indicated that the groundwater concentrations are reducing in the monitoring wells. During the second round of injections soil samples will be taken, and at least 50% higher amount of Potassium Permanganate will be injected into the subsurface via several direct-push wells within the area of the remaining contamination. Alyce Hughey
7/16/2010 Document, Report, or Work plan Review - other Reviewed the March 2010 Monitoring Event Report, dated May 2010, from MWH for Paul Horwath. The March of 2010 groundwater sampling indicates that the GRO concentrations are decreasing within MW-2. The use of potassium permanganate as a chemical oxidation treatment appears to be effective in decreasing the concentrations within the groundwater at the site. Future groundwater monitoring, and the installation of confirmation soil boring samples will confirm the effectiveness of the potassium permanganate treatments performed at the site. Alyce Hughey
11/16/2010 Meeting or Teleconference Held Staff attended the annual environmental planning meeting with Tesoro and MWH to discuss the workplans for 2011. Alyce Hughey
11/16/2010 Meeting or Teleconference Held Staff attended the annual environmental planning meeting with Tesoro and MWH to discuss the workplans for 2011. Paul Horwath
2/1/2011 Document, Report, or Work plan Review - other Reviewed the October 2010 Monitoring Event Report, dated December 2010, from MWH. The October 2010 groundwater sampling indicates that the GRO and DRO concentrations in MW-2 are above the groundwater cleanup levels, with a decrease in GRO concentrations from March to October of 2010. MW-3 detected GRO at 0.0515 mg/L and all the other analytes were not detected in the samples taken. The remediation activities conducted in 2010 included chemical oxidation to address the remaining soil and groundwater impacts, and confirmation soil borings. A report will be submitted in the future discussing the potassium permanganate treatments and the results of the confirmation soil borings taken. Alyce Hughey
3/17/2011 Document, Report, or Work plan Review - other Reviewed and approved the March 16, 2011 Field Scale Pilot Study for Chemical Oxidation Treatment Corrective Action Plan, from MWH. The corrective action plan includes the application of Sodium Persulfate for In-Situ Chemical Oxidation for treatment of the petroleum contaminated soil and groundwater. Paul Horwath
4/27/2011 Document, Report, or Work plan Review - other Reviewed the 2010 Chemical Oxidation and Soil Boring Report, dated March 2011, from MWH. The findings of the field parameters after the October 2009 potassium permanganate injection were a notable decrease in pH and an increase in oxidation reduction. The field parameters could not be verified after the April 2010 injection due to the erratic readings and difficulty calibrating the field instrument. The groundwater concentrations showed an increase in GRO and DRO in MW-2 after the first round of injections with a continual increase after the second round of injections, also, with an increase in DRO concentrations seen in MW-3 after the second round of injections. It is thought that the increase in concentrations is caused by the contact of the potassium permanganate with the contaminants thereby mobilizing the contaminants. The findings of the soil boring concentrations showed that some areas of previous contamination have significantly decreased SB-2, SB-3, SB-4, and SB-8 while others have not changed SB-5, SB-6, and SB-7. Alyce Hughey
6/22/2011 Document, Report, or Work plan Review - other Reviewed the February 2011 Monitoring Event Report, dated May 2011, from MWH. The February 2011 groundwater sampling indicated that Benzene, Ethylbenzene, GRO and DRO groundwater contamination still remains in MW-2. These concentrations are similar with results of the July of 2009 sampling. It is thought that the variable concentrations might be attributed to contaminant desorption resulting from the ongoing chemical oxidation injections performed at the site. Monitoring well MW-3 tested undetected for all analytes. It was noted during the February monitoring event that most of the monitoring wells had heaved during the winter and it is planned for the wells to be cut down and resurveyed during the second quarter of 2011. Alyce Hughey
10/7/2011 Document, Report, or Work plan Review - other Reviewed the August 2011 Monitoring Event Report, dated September 2011, from MWH. The August 2011 groundwater sampling showed a decrease in concentrations within MW-2, with DRO the only analyte testing above the groundwater cleanup levels at 2.39 mg/L. Monitoring well MW-3 tested undetected for all analytes other than DRO at a concentration of 0.509 mg/L. Alyce Hughey
10/19/2011 Update or Other Action Reviewed the additional information received regarding the integrity of the monitoring wells due to heaving during the winter months as was noted in the February Monitoring Event report. MW-2 was cut down about 1.75", and all the rest of the wells were in good condition. The wells were surveyed in and the groundwater flow and gradient was calculated. Groundwater was flowing with a northwesterly flow direction at 341 degrees, and gradient of 0.0013, which is consistent with previous events. Alyce Hughey
12/1/2011 Meeting or Teleconference Held Staff attended the annual environmental planning meeting with Tesoro and MWH to discuss the workplans for 2012. Alyce Hughey
12/1/2011 Meeting or Teleconference Held Staff attended the annual environmental planning meeting with Tesoro and MWH to discuss the workplans for 2012. Paul Horwath
1/5/2012 Document, Report, or Work plan Review - other Reviewed the 2011 Chemical Oxidation Pilot Study Report, dated November 2011, from MWH. On June 11, 2011 the in-situ chemical oxidation was performed using Sodium Persulfate in two subsurface injection points in the area of the residual soil contamination. The injections were advanced to 18 feet below ground surface, with 275-gallons of 12 percent Sodium Persulfate solution and activated with 140-gallons of 8 percent hydrogen peroxide. Monitoring well MW-2 was used to conduct field measurements one day prior; two, nine, sixteen, twenty-four and sixty-eight days after, the injection. The biggest difference was observed two days after the injection, with measurements returning to pre injection parameters within a week or so after the injection. Laboratory intrinsic parameters were conducted for Sodium and Total Organic Carbon. The biggest difference was observed two days after the injection with sodium at 395,000 ug/l and total organic carbon at 18.8 mg/L. These levels returned to approximately pre-injection levels within a couple of weeks after the injection. The results of the groundwater sampling conducted sixty-eight days after the injection showed an increase in all analytes with DRO being detected above the groundwater cleanup levels in MW-2. It is believed that the increase may be caused by a reaction of the chemical oxidant with the contaminants, thereby possibly mobilizing the contaminants. Two soil borings were advanced in the area of the injections with soil sample results detecting Ethylbenzene at 19.6 mg/kg, Xylenes at 107 mg/kg, GRO at 1,560 mg/kg, and DRO at 368 mg/kg at twenty feet below ground surface. Alyce Hughey
2/16/2012 Exposure Tracking Model Ranking A new updated ranking with ETM has been completed for source area 77811 Former USTs. Alyce Hughey
4/10/2012 Document, Report, or Work plan Review - other Reviewed the February 2012 Monitoring Event Report, dated April 2012, from MWH. During the February 24, 2012 groundwater sampling event, all site monitoring wells, MW-1 through MW-7, and the drinking water well located cross-gradient from the site at OK Beauty Salon were sampled. DRO was detected at 2.37 mg/L above the groundwater cleanup levels in MW-2, and DRO was detected at concentrations below the groundwater cleanup levels in MW-1, MW-3, MW-4, and MW-6. Benzene, Toluene, Ethylbenzene, Xylenes and GRO were detected at concentrations below the groundwater cleanup levels in MW-2. The drinking water well at OK Beauty Salon did not detect any analytes in the drinking water sample collected on October 11, 2011. Alyce Hughey
4/27/2012 Exposure Tracking Model Ranking A new updated ranking with ETM has been completed for source area 77811 Former USTs. Paul Horwath
4/27/2012 Exposure Tracking Model Ranking Initial ranking with ETM completed for source area id: 77811 name: Former USTs Paul Horwath
5/3/2012 Cleanup Complete Determination Issued Following the completion of remedial action performed at this site from 1996 to 2011, residual soil contamination remains in the subsurface soil exceeding the ADEC’s Method Two ‘Migration to Groundwater’ soil cleanup levels in the area along the northern and western property boundaries along West Fireweed Land and Spenard Road. Residual groundwater contamination remains on site exceeding the ADEC’s Table C Groundwater Cleanup Levels. The affected groundwater is not currently used as a drinking water source, and the site is serviced by the City of Anchorage public water and sewer systems. The most current soil sample analytical data reported BTEX, GRO, and DRO contamination exceeding the applicable soil cleanup levels, along the northern and western property boundary, along West Fireweed Lane and Spenard Road. Any proposal to excavate, transport, move, treat, and/or dispose of residual contaminated soil at this “site” requires prior ADEC approval. Municipal public water service is currently provided to this property. Water wells may not be installed on this property without the prior notification, and approval, of ADEC. All groundwater monitoring wells, treatment wells, and subsurface treatment piping associated with this project must be properly decommissioned in accordance with ADEC’s November 2011 Monitoring Well Guidance. Decommissioning work should be completed when frost is not present in the soil. The decommissioning of these wells and any subsurface treatment piping should occur before August 30, 2012, and must be documented in a written report submitted to ADEC by November 30, 2012. Paul Horwath
5/3/2012 Long Term Monitoring Complete Administrative action on 5/1/2013. Kristin Thompson
6/6/2012 Meeting or Teleconference Held Staff attended the mid-year planning meeting at the ADEC office in Soldotna to discuss the decommissioning of monitoring wells and the recording of the Notice of Environmental Contamination for the site. Alyce Hughey
7/17/2012 Document, Report, or Work plan Review - other Reviewed the Decommissioning Work Plan for 2012, dated July 12, 2012, prepared by MWH, and issued a conditional approval to decommission MW-4, MW-5, MW-6, MW-7, SVE/MW-1, SVE/MW-2, SVE/MW-3 and AS-1. Conditions include 1) Our understanding and interpretation of this work plan is that a bentonite grout slurry will be used to fill the voids left during removal of the MW casings, and to pressure grout any piping associated with SVE/AS wells and subsurface delivery piping to be left in the subsurface. The use of bentonite chips or non-grout should only be substituted with our prior approval. There are drilling contractors preferring to use dry bentonite chips or pellets, but the drilling contractor shall not be allowed to take control of this field work and substitute dry/solid bentonite chips or pellets without prior ADEC approval. 2) Following the completion of this work, a written report documenting the implementation and completion of these approved work tasks shall be prepared and provided to our office, complete with the signature of the “qualified person” responsible for observing and documenting the field work. Paul Horwath
11/14/2012 Meeting or Teleconference Held Paul Horwath and Alyce Hughey attended annual planning meeting at MWH office in Anchorage to discuss the decommissioning activities conducted at the site in 2012. Alyce Hughey
1/2/2013 Document, Report, or Work plan Review - other Reviewed the August 2012 Monitoring Wells/Remediation System Decommissioning Report, dated November 6, 2012, from MWH. On August 22, 2012 four groundwater monitoring wells (MW-4, MW-5, MW-6 and MW-7), one air sparge well (AS-1), and three combination soil vapor extraction/monitoring wells (SVE/MW-1, SVE/MW-2 and SVE/MW-3) were decommissioned in accordance to the approved July 12, 2012 Decommissioning Work Plan for 2012 Former Tesoro 2 Go Mart #9 and ADEC’s July 17, 2012 e-mail correspondence with conditions. Alyce Hughey

Contaminant Information

Name Level Description Media Comments
DRO Between Method 2 Migration to Groundwater and Human Health/Ingestion/Inhalation Soil
GRO Between Method 2 Migration to Groundwater and Human Health/Ingestion/Inhalation Soil
DRO > Table C SoilGroundwater
BTEX Between Method 2 Migration to Groundwater and Human Health/Ingestion/Inhalation Soil

Control Type

Type Details
No ICs Required

Requirements

Description Details
Advance approval required to transport soil or groundwater off-site.

No associated sites were found.

Missing Location Data

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